The six “farmers” who were arrested are believed to have been working there full-time and lived on-site.

According to Staffordshire Police, three men were detained at the scene and the other three men were arrested following a police search of the area, which included support from the National Police Air Service, in connection with the production of cannabis.

The men, aged between 17 and 44 years, are from the UK and Albania.

Inspector Richard Meaden, South Staffordshire local policing commander, said: “The investigation is at an early stage, however we can confirm that approximately 3,100 cannabis plants were recovered. This estimated value of this crop is estimated to be worth £1.5 million.

“This is the largest and most sophisticated cannabis factory I’ve ever experienced and I am delighted we have been able to take such a large number of drugs off the streets.”